The resolution limit of the eye is 1 minute.At a distance x km from the eye,two persons stand with a lateral separation of 3 km.For the two persons to be just resolved by the naked eye,x should be

P is a point on either of the two lines y - sqrt3|x|=2 at a distance 5 units from their point of intersection The coordinates of the foot of the perpendicular from P on the bisector of the angle between them are

A bird is tossing (flying to and fro 0 between two cars moving towards each other on a straight road. On car has a speed of 18 km /h while the other has the speed of 27 km /h. The bird starts moving from first caer towards the other and is moving with the speed of 36 km /h and when the two cars were separated by 36 km. What is the total distance comered by the bird ? What is the total displacement of the bird ?

A paper,with two marks havin separation d,is held normal to the line of sight of an observer at a distance of 50 m.The diamerter of the eye len of he obeserver is 2 mm.the least value of d,so that the marks can be seen as seaarte,will be (The mean wavelength of visible light may be taken as 5000 A )

A farsighted person has a near point of 75 cm for one eye and a near point of 100 cm for the other .What pwers should corrective lenses have to allow the person to see an object clearly at a distance of 25cm.

A telescope has an objective lens of 10 cm diameter and is situated at a distance of 1 km from two objects.The can be resolved by the telescope, when the mean wavelength of light is 5,000 overset @A ,is of the order of

In an experiment to determine the focal length (f) of a concave mirror by the u-v method, a student places the object pin A on the principal axis at a distance x from the pole P. The student looks at the pin and its inverted image from a distance keeping his/her eye in line with PA. When the student shifts his/her eye towards left, the image appears to the right of the object pin. Then,

A picnic is being planned in a school for Class VII. Girls are 60% of the total number of students and are 18 in number. The picnic site is 55 km from the school and the transport company is charging at the rate of Rs 12 perkm and the cost of refreshment is Rs.4280.Find : The amount which has to be taken from each person if two teahers are also to go with them.

An oil company has two depots A and B with capacities of 7000 l and 4000 l respectively. The company is so supply oil to three petrol pumps, D,E and F whose requirements are 4500 l, 3000 l and 3500 l respectively. The distance between the depots and the petrol pumps is given in the following table: Assuming that the transportation of cost of 10 litres of oil is Rs. 1 per km, how should be the delivery be scheduled in order that the transportation cost is minimum? what is the minimum cost?

A colloidal solution is a type of mixture which consists of particles whose size varies between 1 and 1000 nanometres. In colloidal solution the particles are distributed evenly. During this process the particles do not settle down. This is one of the best know thing about colloidal solutions. Properties of colloids and their variation are a well-known area ever since the primitive age. The best example to prove their familiarity with us is that we know from very early times that coagulation of milk results in the formation of curd. Physical properties of colloids 1. The nature of the colloidal solution is heterogeneous i.e. unlike. These solutions dwell with two different phases : • Dispersed medium Dispersed phase. 2. Despite the fact that colloidal dispersions are unlike in description (nature), yet the dispersed fragments are not detectable by the human eye. This is due to the microscopic size of the particles in the solution. 3. The colour of the colloidal dispersion is determined by particles in the solution based on their size. The wavelengths of light that is absorbed will be longer ifthe size of the particle is large. 4. As a result of its size, the colloidal fragments can easily be passed through a traditional filter paper. However, these particles can be filtered by using membranes such as animal, cellophane, and ultrafilters. What are colloidal solution particle.

A colloidal solution is a type of mixture which consists of particles whose size varies between 1 and 1000 nanometres. In colloidal solution the particles are distributed evenly. During this process the particles do not settle down. This is one of the best know thing about colloidal solutions. Properties of colloids and their variation are a well-known area ever since the primitive age. The best example to prove their familiarity with us is that we know from very early times that coagulation of milk results in the formation of curd. Physical properties of colloids 1. The nature of the colloidal solution is heterogeneous i.e. unlike. These solutions dwell with two different phases : • Dispersed medium Dispersed phase. 2. Despite the fact that colloidal dispersions are unlike in description (nature), yet the dispersed fragments are not detectabJe by the human eye. This is due to the microscopic size of the particles in the solution. 3. The colour of the colloidal dispersion is determined by particles in the solution based on their size. The wavelengths of light that is absorbed will be longer ifthe size of the particle is large. 4. As a result of its size, the colloidal fragments can easily be passed through a traditional filter paper. However, these particles can be filtered by using membranes such as animal, cellophane, and ultrafilters. What type of phases of colloidal solutions ?